Lubricants containing poly



United States Patent Ofifice 3,087,892 Patented Apr. 30, 1963 This invention relates to lubricating oil compositions having improved viscosity index characteristics; in particular, this invention is directed to lubricating oil compositions containing new compounds which are effective to improve the viscosity index (V.I.), of lubricating oil compositions.

This application is a continuation-in-part of patent application Serial No. 773,149, filed November 12, 1958, which issued September 18, 1962, as US. Patent No. 3,054,773.

The greater proportion of oils obtainable by refining processes and useful as base oils for lubricating oil compositions have wide variations in viscosity characteristics with changes in temperature. They do not have agents specifically incorporated therein for the purpose of imparting reduced changes in viscosity with changes in temperature. That is, at a particular temperature, a lubricating oil may be quite viscous, while at higher temperatures the lubricating oil may have a viscosity of a fluid such as kerosene. In order that the viscosity of a lubricating oil composition will not change rapidly with changes in the temperature of an internal combustion engine, for example, numerous additives have been designed to modify the viscosity-temperature characteristics of lubricating oils. The changes in the viscosity occurring with variations in temperature are kept at a minimum.

Polymeric additives in general are used to improve the viscosity-index characteristics of lubricating oil compositions. Such polymeric additives include, for example, alkyl methacrylate polymers (cg, polybutyl methacrylate), and polyolefins (cg. polybutenes). These additives are known to improve the viscosity-temperature relationships of lubricating oils.

The art is replete with numerous viscosity index improving agents. However, the known viscosity index improving agents (e.g., polyalkylrnethacrylates) decompose at high temperatures.

Thus, it is a primary object of this invention to set forth lubricating oil compositions containing new compounds which are thermally stable and which improve the viscosity-temperature characteristics of lubricating oil compositions, including lubricating oil compositions used in an atmosphere of nuclear radiation.

In accordance with this invention, it has been discovcred that lubricating oil compositions containing diphenylcther-p-xylylenc copolymers i.e., poly(dipl1enyl-ether-pxylylencs) have improved viscosity index characteristics.

The poly('diphenylether-p-xylylenes) of this invention are described by the formula:

on. I

wherein R represents branched or straight-chain hydrocarbon radicals containing from 2 to 20 carbon atoms; n, 0, and p are numbers from to 3; and X is a number representing the number of monomeric units in the polymer.

It is preferred that R is an alkyl radical containing from 2 to 20 carbon atoms. Examples of R radicals 2 include methyl, ethyl, propyl, butyl, hexyl, heptyl, octyl, nonyl, dodecyl, tetradecyl, hexadecyl, octadecyl, etc.

The poly(diphenylether-p-xylylenes) can be prepared by first reacting diphenylether with a,a'-dichloro-p-xylene in the presence of a FriedehCrafts catalyst to form a copolymer as represented by the following equation:

wherein X is the same as described hereinabove.

Prior to the reaction with a,on'dlChl0rO- -xylenc, the diphenylether may be alkylated. This alkylated diphenylether may be represented by the following formula:

I (R) u 0 t :1

(III) wherein R, n, 0 and p are the same as defined hereinabove, and n+o+p has a value of at least 1.

The polymeric materials described herein can be prepared by bulk or solution Friedel-Crafts polymerization reactions. The Friedebcraits catalysts which can be used include ferric chloride, aluminum chloride, aluminum bromide, etc. Such catalysts are used in amounts of about 0.01% to about 1.0% by weight. The mol ratio of diphenylether to a,o=-dichloro-p-xylene can be in the range of 10:1 to 1:1, preferably from 2:1 to 1:1.

Alkylation catalysts include aluminum chloride, hydrofluoric acid, etc.

A dipbenylether will react with a,a'dichloro-p-xylene at temperatures ranging from 65 C. to 150 C. For best results in this reaction, it is preferred to use temperatures ranging from C. to C.

The various solvents which can be used in the polymerization reactions include chloroform, odichlorobenzene, nitrobenzene, etc.

The molecular weight of the resulting polymeric compounds ranges from about 10,000 to about 50,000. That is, the molecular weight of the alkylated diphenylether-pxylylene copolymers are in the range of about 10,000 to about 50,000.

As V.I. improving agents, the poly(diphenylether-pxylylenes) described herein can be used in amounts of 1% to 20%, by weight, in a wide variety of oils, including mineral oils, such as naphthenic base, paral'fin base, and mixed base oils derived from petroleum; synthetic oils, such as polymers of alkylene oxides; aromatic-type oils, such as alkylphenyl diethers, alkylbiphenyls, alkylbiphenyl others, polyalkyl terephcnyls, polyphenyls, polyarylalkanes, dialkylbenzenes, aryl esters, etc.

The new viscosity index improving agents described herein can be prepared by reacting a diphenylether (or an alkyiated diphenylether) with a,a'-diehloro-p-xylene,

using, as a catalyst, from 0.01% to 1.0%, by weight, of anhydrous aluminum chloride, based on the total weight of diphenylether and a,a'dichlorop-xylene, at temperatures from 65 C. to 150 C. for a period of time from 0.5 hour to 30 hours.

The resulting reaction mixtures can be dissolved in benzene, followed by filtration. An acetone-methanol blend (2 parts by volume of methanol per volume of acetone) is added to the benzene solution to precipitate the polymer. The polymers are redissolved in benzene and reprecipitated with an acetone-methanol blend. The resulting products can be dried in a vacuum oven at temperatures of about 100 C. The resulting polymeric compound can then be alkylated with a hydrocarbon containing from 2 to 20 carbon atoms, using hydrofluoric acid as a catalyst.

Example I hereinbelow illustrates the preparation of the new compounds of this invention.

EXAMPLE I-ALKYLATED POLY (DIPHENYLETHE R-pXYLYLENE) A mixture of 15 grams (0.086 mol) of a a,rx'-dichloropylene to benzene ring of 351, was dissovled in 225 grams of ferric oxide, and 0.05 gram ferric chloride was heated on a steam plate at 100 C. to 105 C. for less than 0.5 hour. The resulting polymer was dissolved in benzene and the benzene solution was filtered. An acetonemethanol blend (2 volumes methanol per volume acetone) was added to precipitate the polymer, which was recovered and dried. A 10% solution of this polymer in toluene had a viscosity of 1.81 cs. at 100 F.

A mixture of 10 grams of the above diphenylether-pxylylene copolymer and 59 grams of a polypropylene (i.e., a propylene tetramer) in a mol ratio of polypropylene to benzene ring of 3:1, was dissolved in 225 grams of o-dichloro-benzene. This mixture was reacted in the presence of 150 cc. of hydrofluoric acid as a catalyst for a period of 4 hours at 5 C. The reaction mixture was poured into cold dilute caustic solution. The reaction product was separated and water Washed, and washed with dilute sodium bicarbonate, then dissolved in benzene. The benzene solution was blended with an acetone-methanol blend to precipitate the product. The product was a tacky, benzene soluble polymeric compound. The viscosity of a solution of this polymer in toluene was 2.55 cs.

Table I hereinbelow presents data to show the etfectiveness of the polymeric compound of Example I hereinabove as a viscosity index improving agent in lubricating oil compositions. The alkylated copolymer was blended into (A) a C1446 alkyl diphenylether, and (B) a California solvent refined naphthenic base oil having a viscosity of 150 SSU at 100 F.

EXAMPLE IIALYKLATED POLY (DIPHENYL ETHER-p-XYLYLENE) A mixture of 35 grams of a poly(diphcnyl ether-pxylylene) (wherein the mol ratio of diphenyl ether to a,a'-dichloro-p-xylene in the initial reaction had a value of 1.2), 200 grams of a propylene tetrarner (the same as used in Example I hereinabove) (the mol ratio of the tetramer to benzene rings of the copolymer being 3:1), 300 cc. of o-dichlorobcnzene and 300 cc. of hydrofluoric acid were charged to a reaction vessel at 5 C. The components of the above mixture were agitated for a period of 4 hours at 5 C., after which the reaction prodnot was obtained in a manner similar to that outlined hereinabove in Example I.

A 10% solution of the recovered polymer in toluene had a viscosity (cs.) at 100 F. of 8.58.

Table II hereinbelow presents data showing the efiectivcness of these polymers of Example II as V.I. improving agents in lubricating oils. The base oils was a C1445 alkyl diphenyl ether.

Table II 100 F. 210 F. v1.

EXAMPLE III.PREPARATION OF POLY (ALKYLATED BIS-(p-PHENOXYPHENYL) ETHER-p-XYLYLENE A mixture of 35 grams of bis(pphenoxyphenyl) r ether-p-xylylene copolymer, 200 grams of a propylene tetramer (the mol ratio of tetramer to benzene ring being from 3:1), 315 grams of o-dichlorobenzene and 200 cc. of hydrofluoric acid agitated at 5 C. for a period of 2 hours. 100 cc. of hydrofluoric acid Was added to the above blend, after which the mixture was agitated for an additional 4 hours at 5 C. The reaction product was recovered in a manner described hereinabove in Example I.

A 10% solution of the recovered polymer in toluene had a viscosity of 1.92 cs. at 100 F.

Table III hereinbelow presents data obtained to show the elfectiveness of the alkylated copolymers of Example III as V.I. improving agents. The base oil was a C alkyl diphenyl ether.

Table III 100 F. 210 F. V. I

EXAMPLE IV.-POLY(ALKYLATED DIPHENYL- ETHERp-XYLYLENE) A mixture of grams (0.4 mol) of a,tx'-dichloro-pxylene, 168 grams (0.44 mol) of C1446 sec-alkyl diphenyl ether, 20 cc. chloroform, 0.01 gram ferric oxide, and 0.05 ferric chloride was heated at to C. for a period of about 1.3 hours. During the course of the reaction, 100 cc. of o-dichlorobenzene was added slowly to keep the reaction mixture fluid.

The mixture was refluxed with cc. xylene in the presence of 0.05 gram aluminum chloride for 1.5 hours, after which the mixture was filtered. The polymeric compound was dissolved in benzene, to which was added a methanol-acetone blend to precipitate the product which was dried in vacuo.

A 10% solution of this polymer in toluene had a described herein are of greater thermal stability than prior V.I. improving agents. In order to determine the thermal stability thereof, the new compounds were incorporated in a base oil consisting of an alkyl diphenyl viscosity of 3.7 cs. at 100 F. 5 p I Table IV hereinbelow presents data obtained to show ether wheiem the alkyl group was derived from mono the efiecfiveness of the polymers of Example Iv as Vl olefins having an average of 14 to 16 carbon atoms. The improving agents. Base oil (A) was a. C1446 al resulting solution was heated at the temperatures noted phenylether. Base oil (B) was a California petroleum and the PfiIlOd f tlme dwgnated, after which 111% base oil. 10 cosities were determined.

Table VI Viscosity Concen- V.I. lmtratlon Test Test Before test After test proving (weight temp, time, agent percent) F. hours Per- Per- 100 F. 210 F. 100 F. cent 210 F. cent change change 4.2 500 as 69.0 11.8 56.3 -19.2 9 44 -2u3 600 a 69.6 11.3 48.2 3a.? 7.95 -3as X Alkylated (Cm) diphenyl ether-p-Xyiylene copolymer.

Table IV I claim:

30 1. A lubricating oil composition consisting essentially of major proportion of an oil of lubricating viscosity, and, Base on Pprcem hmsmesics) in an amount sufficient to improve the viscosity index polymer 0 o 7 thereof, a polymeric compound having a molecular weight 100 i 210 v in the range of 10,000 to about 50,000 obtained by react- 4 ing a diphenyl ether with an u,a'-dichloro-p-xylene in the (A) g 221% $133 presence of a Friedel-Crafts catalyst at temperatures in 10 112.0 19.1 1%? the range of 90 C. to 120 0., and removing the HCl (B) S obtained by said reaction.

5 5 8 135 2. A lubricating oil composition consisting essentially 10 92.3 14.9 141 4g 1660 2543 139 of a rumor proportion of an 011 of lubricating viscosity, and, in an amount suflicient to improve the viscosity index Table V hereinbelow presents further data concerning the effectiveness of the polymeric compounds described herein as VxI. improving agents. Base oils (A) and (B) were the same as described heremabove.

Table V Viscosity Percent Viscosities ((-s.) Alkylatedd of 10?, sol. alkylated Base 01 her use in to none 0 mer 0 p y} D y 100 F. 210 F. V1.

( 1.76 5 (A) 42. 7 7. 134 10 (A) 67.9 11.0 130 15 (A) 107. 0 16. 3 138 3. 5 (A) 57. 1 9. 89 143 10 (A) 115. 0 19.0 143 15 (A) 219 34. 6 138 5 (B) 56. 9 9. 04 134 10 (B) 105. 0 16. 3 139 15 (B) 95. 0 28. 6 137 5 (A) 64.5 11.0 143 1. 29 5 (A) 36. 8 6. 27 128 10 (A) 50. 9 8.17 132 15 (A) 71. 0 10. 7 133 5 (B) 40.4 0. 26 113 10 (B) 52. 1 7. T2 120 15 (B) 72. 5 10. 1 124 2. 5 (A) 50.1 S. 62 140 10 (A) 92. 1 l5. 3 143 15 (A) 168. 0 26. 5 140 5 (B) 56. 1 8. 54 128 10 13) 103.0 15.0 135 15 B) 187.0 26. 2 136 1 Poly (n-nonyl, scc-dodecyldiphenylether-p-Xylylene).

2 Poly [d1(C1B-C1S. sec alk l) d1phenylether'p-xylylene]. wherein the mol ratio of Cm to (,1B was 32 2 08.

Poly n-nonyl diphenylether-p-xylylene),

Poly dfln-nonyll1 (liphenylether-p-xylylene].

a Potytdodecyldip enyletherp-xylylene) wherein there were at least 3 dodecyl radicals per benzene ring.

As stated hereinabove, the new V1. improving agents thereof, a polymeric compound having a molecular weight in the range of 10,000 to about 50,000 obtained by reacting a diphenylether with an a,a'-dichloro-p-xylene in the presence of a Friedel-Crafts catalyst at temperatures in the range of C. to (1., wherein the moi ratio of said diphenylether to said xylene is from 10:1 to 1:1 and removing the HCl obtained by said reaction.

3. A lubricating oil composition comprising an oil of lubricating viscosity in major proportion, and, in an amount sufficient to improve the viscosity index thereof, a resinous condensation product having a molecular weight in the range of 10,000 to 50,000 obtained by reacting an alkyl diphenylether with an a,a-dichloro-pxylene in the presence of a Friedel-Crafts catalyst at ternperatures in the range of 90 C. to 120 C., and removing the resulting HCl.

4. A lubricating oil composition consisting essentially of an oil of lubricating viscosity in major proportion, and, in an amount suflicient to improve the viscosity index thereof, a polymeric compound having a molecular weight in the range of 10,000 to 50,000 octane by reacting an alkyl diphenylether with an u,oz'-dichloro-p-xylene in the presence of a Friedel-Crafts catalyst at temperatures in the range of 90 C. to 120 C., and removing the resulting HCl, wherein said alkyl radical contains from 2 to 20 carbon atoms.

5. A lubricating oil composition having incorporated therein for the purpose of improving the viscosity index thereof, from 1% to about 20%, by weight, of a polymeric compound having a molecular weight in the range of about 10,000 to about 50,000 obtained by reacting an alkyl diphenylether with an a,a-dichloro-p-xylylene in the presence of a Friedel-Crafts catalyst at temperatures in the range of 90 C. to 120 C., and removing the resulting HCl, and wherein said diphenylether contains from 1 to 3 alkyl radicals on each phenyl ring, and wherein said alkyl radical contains from 2 to 20 carbon atoms.

6. A lubricating composition consisting essentially of a major proportion of an oil of lubricating viscosity, and from about 1% to about 20%, by weight, of a polymeric compound having a molecular Weight in the range of about 10,000 to about 50,000 obtained by reacting an alkyl diphenylether with an u,ot'-dichloro-p-xylene in the presence of a Friedel-Crafts catalyst at temperatures in the range of 90 C. to 120 C., and removing the resulting HCl, wherein the mol ratio of said diphenyl-ether to said xylylene is from 10:1 to 1:1, and said diphenyl- 8 ether contains from 1 to 3 alkyl radicals on each phenyl ring, and wherein said alkyl radical contains from 2 to 20 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 2,060,715 Arvin Nov. 10, 1936 2,355,616 Barker Aug. 15, 1944 2,542,111 Bloch Feb. 20, 1951 2,911,380 Doedens Nov. 3, 1959 2,965,607 Martin et al. Dec. 20, 1960 3,006,852 Barnum et al. Oct. 31, 1961 

1. A LUBRICATING OIL COMPOSITION CONSISTING ESSENTIALLY OF MAJOR PROPORTION OF AN OIL OF LUBRICATING VISCOSITY, AND, IN AN AMOUNT SUFFICIENT TO IMPROVE THE VISCOSITY INDEX THEREOF, A POLYMERIC COMPOUND HAVING A MOLECULAR WEIGHT IN THE RANGE OF 10,000 TO ABOUT 50,000 OBTTAINED BY REACTING A DIPHENYL ETHER WITH A,A''-DICHLORO-P-XYLENE IN THE PRESENCE OF A FRIEDEL-CRAFTS CATALYST AT TEMPERATURES IN THE RANGE OF 90*C. TO 120*C., AND REMOVING THE HCI OBTAINED BY SAID REACTION. 